Backlight module, holographic display device and holographic display method thereof

Abstract

A backlight module, a holographic display device and a holographic display method thereof are provided. The backlight module includes a semi-transparent layer and a reflective layer which are disposed opposite to each other, a light source, and a deflectable optical device. The light source is configured to emit a light beam, the deflectable optical device is configured to deflect a propagation direction of the light beam emitted from the light source and make the reflected light beam enter between the semi-transparent layer and the reflective layer in an angle, and is deflectable to change the angle.

What is claimed is: 
     
       1. A backlight module, comprising:
 a semi-transparent layer; 
 a reflective layer, disposed opposite to and spaced from the semi-transparent layer; 
 a light source, configured to emit a light beam; and 
 a deflectable optical device, configured to deflect a propagation direction of the light beam emitted from the light source, make the light beam enter between the semi-transparent layer and the reflective layer in a direction and be deflectable to change the direction, 
 wherein the semi-transparent layer comprises a first region and a second region disposed at a periphery of the first region, an orthographic projection of the reflective layer on the semi-transparent layer is totally overlapped with the first region, and the deflectable optical device is disposed at a position facing the second region, 
 wherein the second region comprises a first sub-region and a second sub-region which are adjacent and connected to each other, the deflectable optical device comprises a first sub deflectable optical device disposed at a position facing the first sub-region, and a second sub deflectable optical device disposed at a position facing the second sub-region. 
 
     
     
       2. The backlight module according to  claim 1 , wherein the semi-transparent layer is configured to reflect a part of a light beam striking the semi-transparent layer and transmit the remaining part of the light beam. 
     
     
       3. The backlight module according to  claim 1 , wherein the semi-transparent layer and the reflective layer are disposed parallel to each other, so that a part of the light beam entering between the semi-transparent layer and the reflective layer is reflected between the semi-transparent layer and the reflective layer for multiple times. 
     
     
       4. The backlight module according to  claim 1 , wherein the deflectable optical device comprises a reflective mirror or a deflecting lens. 
     
     
       5. The backlight module according to  claim 1 , wherein an end portion of the reflective layer is provided with an opening, the opening is configured to allow the light beam deflected by the deflectable optical device to enter between the semi-transparent layer and the reflective layer. 
     
     
       6. The backlight module according to  claim 1 ,
 wherein the light source is configured to respectively emit a first light beam to the first sub deflectable optical device and a second light beam to the second sub deflectable optical device, the first sub deflectable optical device is configured to deflect a propagation direction of the first light beam, make the first light beam enter between the semi-transparent layer and the reflective layer in a first direction and be deflectable to change the first direction, the second sub deflectable optical device is configured to deflect a propagation direction of the second light beam, make the second light beam enter between the semi-transparent layer and the reflective layer in a second direction and be deflectable to change the second direction. 
 
     
     
       7. The backlight module according to  claim 6 , wherein the light source comprises:
 a first sub light source, configured to emit the first light beam; and 
 a second sub light source, configured to emit the second light beam, 
 wherein the first light beam and the second light beam point in opposite directions and are not collinear. 
 
     
     
       8. The backlight module according to  claim 1 , wherein the deflectable optical device comprises:
 a spindle; and 
 an optical device, sleeved on the spindle, 
 wherein the optical device is configured to deflect along with a rotation of the spindle. 
 
     
     
       9. The backlight module according to  claim 1 , further comprising:
 a collimating lens, disposed between the light source and the deflectable optical device and configured to collimate the light beam emitted by the light source. 
 
     
     
       10. The backlight module according to  claim 1 , wherein the light source is configured to emit coherent light. 
     
     
       11. The backlight module according to  claim 1 , wherein the light source is disposed at a side of the reflective layer away from the semi-transparent layer. 
     
     
       12. A holographic display method of a holographic display device, wherein the holographic display device comprises a backlight module, a spatial optical modulator, a camera, and a controller, the backlight module comprises the backlight module according to  claim 1 , the spatial optical modulator is disposed at a side of the semi-transparent layer away from the reflective layer, the holographic display method comprises:
 acquiring, by the camera, a human eye position of a current user; and 
 controlling, by the controller, the deflectable optical device to deflect to adjust an observation range of the holographic display device according to the human eye position. 
 
     
     
       13. The holographic display method according to  claim 12 , wherein the light source is configured to respectively emit a first light beam to the first sub deflectable optical device and a second light beam to the second sub deflectable optical device, the first sub deflectable optical device is configured to deflect a propagation direction of the first light beam, make the first light beam enter between the semi-transparent layer and the reflective layer in a first direction and be deflectable to change the first direction, the second sub deflectable optical device is configured to deflect a propagation direction of the second light beam, make the second light beam enter between the semi-transparent layer and the reflective layer in a second direction and be deflectable to change the second direction, the holographic display method comprises:
 controlling, by the controller, the light source to emit the first light beam or the second light beam according to the human eye position; and 
 controlling, by the controller, the first sub deflectable optical device or the second sub deflectable optical device according to the human eye position to adjust the observation range of the holographic display device. 
 
     
     
       14. A holographic display device, comprising:
 a backlight module; and 
 a spatial light modulator, 
 wherein the backlight module comprises the backlight module according to  claim 1 , the spatial light modulator is disposed at a side of the semi-transparent layer away from the reflective layer. 
 
     
     
       15. The holographic display device according to  claim 14 , wherein the spatial light modulator is a liquid crystal spatial light modulator. 
     
     
       16. The holographic display device according to  claim 14 , further comprising:
 a camera, configured to capture a human eye position of a user; and 
 a controller, communicably connected with the camera and the deflectable optical device and configured to control the deflectable optical device to deflect according to the human eye position. 
 
     
     
       17. The holographic display device according to  claim 14 , further comprising:
 a lens, disposed at a side of the spatial light modulator away from the backlight module.